Axially reciprocating screw conveyor means for closing tap hole



April 21, 1970 w. RESCH EI'AL AXIALLY RECIPROCATING SCREW CONVEYOR MEANSFOR CLOSING TAP HOLE Filed 001:. 31. 1967 United States Patent 3,507,483AXIALLY RECIPROCATING SCREW CONVEYOR MEANS FOR CLOSING TAP HOLE WernerResch, Dortmund-Kirchhorde, and Oskar Fliege,

Dortmund, Germany, assignors to Hoesch Aktiengesellschaft, Dortmund,Germany Filed Oct. 31, 1967, Ser. No. 679,480 Claims priority,application Germany, Nov. 3, 1966, H 60 917 US. Cl. 26642 8 ClaimsABSTRACT OF THE DISCLOSURE A screw conveyor extends with a front portionthereof into a hole in the masonry structure, and a rear portion extendsoutwardly beyond the structure. A feed for a hardenable mortarcommunicates with the rear portion and supplies thereto quantities ofthe mortar. Drive means is connected with the screw conveyor and servesto rotate the same whereby to convey the mortar from the rear portiontowards the front portion and beyond the same into the hole, and foraxially reciprocating the screw conveyor to thereby effect tamping ofthe mortar which has been conveyed into the hole.

BACKGROUND OF THE INVENTION The present invention relates generally toan apparatus for closing a hole in a masonry structure, and moreparticularly for an apparatus for closing the tap hole in a wall of anopen hearth furnace.

The most commonly used method of making steel is the so-calledopen-hearth furnace process. Such openhearth furnaces are well known andneed not be described in detail. For the purposes of the presentinvention it will be sufficient to point out that the furnace proper isa masonry structure usually of rectangular configuration, which issupported by steel buckstays which are united via steel struts and tierods. When the heat has been mixture of such slag with the dolomiteadversely influences the closure which is provided when the dolomitehardens, and therefore can bring with it the danger of steel break-outduring operation of the furnace. Of course, it is clear that thedolomite cannot simply be loosely introduced but must be tamped andcompacted to provide a proper plug when it hardens.

All of this is customarily accomplished manually and it is clear thatthis is hard and tiring work. In view of the fact that the condition andsize of the tap hole frequently differ, and taking in conjunction thiswith the strenuousness of the closing operation, it will be clear thatthe quality of the closure which is obtained varies greatly frominstance to instance. If, however, the closure permits molten steel tobreak out before the proper time is reached, this cannot only bring withit dangers to the operating personnel as already mentioned briefly, butwill also result in a steel which is so inferior that it must bereintroduced into the furnace for re-melting. Evidently, this is timeconsuming and expensive, and reduces very significantly theeffectiveness and economic operation of the furnace.

SUMMARY OF THE INVENTION The present invention overcomes theaforementioned disadvantages.

More particularly, the present invention provides an apparatus which isgenerally suitable for closing a hole in a masonry structure with ahardenable mortar and which is particularly suitable for closing the taphole in the wall of an open hearth furnace.

The apparatus in accordance with the present invention is relativelysimple in its construction and requires no significant economic ortechnological investments.

Furthermore the apparatus disclosed herein is highly reliable in itsoperation and eliminates the need for manual labor in closing the taphole. What is more, the apparatus according to our invention does notrequire a skilled operator to supervise it.

By employing the apparatus disclosed herein closing melted and thefinishing temperature is reached, the heat of steel is ready to betapped, that is to be removed from the furnace. For this purpose thefurnace is provided, usually midway between the ends of the hearth, witha so-called tap hole which, before the furnace is charged at thebeginning of the heat, is filled with a suitable mortar, usuallydolomite or a mixture containing this material. This filling mustcompletely close the tap hole and prevent escape of molten steeltherethrough until the heat is ready for tapping. Once this stage in themelting process has been reached the tap hole is opened, either by beingburned out from the tapping side, that is the outer or exposed side ofthe furnace wall, or by a jet tapper consisting of a hollow explosivecharge which concentrates its energy when discharged against theobstruction in the tap hole. The molten steel can now run out of thefurnace.

In preparation for the next following heat, or more particularly for thenext charge which precedes the heat, the tap hole is freed from steelwhich has chilled therein, raked out and cleaned of slag. Thereupon itmust be closed up by introducing the dolomite mortar into the hole. Thisis customarily accomplished by having a helper manually introduce thecoarse-grained dolomite mass into the tap hole, and by having anotherhelper push the mass from the outer side towards the inner side of thetap hole. At the same time, additional dolomite is thrown against theinner end of the tap hole, that is the end within the furnace. Closingof the tap hole must be effected quickly to prevent slag remainingwithin the furnace from entering into the tap hole because a of thefurnace tap hole can be effected more speedily and at less expense thanheretofore known, and a closure of reliable and reproducible qualitywill be obtained in every instance. This eliminates the danger ofpremature break-out of the melt.

In accordance with one feature of our invention We provide an apparatusof the type set forth which includes a screw conveyor whose frontportion is arranged to extend into the tap hole, and whose rear portionextends outwardly beyond the tap hole. A feed or supply is associatedwith the screw conveyor and supplies to the rear portion thereofquantities of hardenable mortar, namely dolomite or adolomite-containing mixture. Finally, a suitable drive arrangement isconnected with the screw conveyor and serves to rotate the same wherebythe mortar is conveyed from the rear portion towards the front portionand beyond the same into the hole and further for axially reciprocatingthe screw conveyor to thereby periodically advance the front portionthereof into en-z gagement with the mortar which has been conveyed intothe hole. By this expedient the mortar already in the hole is tamped andcompacted.

Advantageously, a biasing means is provided which connects the apparatuswith the masonry structure in which the hole is provided, and which isoperative for urging the front portion of the screw conveyor deeper intothe hole. We have also found it advisable to provide suitable cooling,for instance by means of a wateror otherwise fluid-cooled coolingjacket, for the screw conveyor.

With our apparatus we obtain a purely mechanical closure of the taphole, eliminating thereby such factors as personnel fatigue and the likewhich, when manual closing of the tap hole is effected, have heretoforemade is impossible to guarantee an absolutely tight closure ofreproducable quality.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING The single figure is a somewhatschematic sectional view illustrating one embodiment of our invention byway of example.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing now the drawing, indetail, it will be seen that the masonry structure, which will here beassumed to be the wall of an open-hearth furnace, is identified withreference designation MS. Provided in the wall MS is the tap hole THwhich extends from the outer exposed side of the wall to the inner side,that is to the interior of the furnace. The metallic supports for thewall MS are generally identified with reference numeral 6.

The apparatus according to our invention comprises,

as is clearly evident from the drawing, a conventionally operating screwconveyor which includes the conveying screw 1 mounted for rotationwithin the tubular housing 4. Advantageously, the housing 4 can becooled and for this purpose it is provided with a doub e wall whichdefines a cooling jacket for the flow of a coolant fluid, such as water,therethrough. The front portion of the screw conveyor extends, asillustrated in the drawing, into the tap hole TH, whereas the rearportion extends outwardly therebeyond. Feed means in form of a feedhopper 5 communicates with the rear portion in conventional manner, andit is clear from the drawing that, when the usually coarse-graineddolomite or dolomite-containing mortar is introduced into the hopper 5,it will enter the screw conveyor and when the conveyor screw 1 thereofis rotated, the conveyor from its point of entry towards the front endof the screw conveyor and the discharged therefrom into the tap pole TH.

The rear portion of the screw conveyor is further provided with anarrangement for reciprocating the conveyor screw 1. This arrangement isidentified generally with reference numeral 2 and is of well knownconstruction so that it need not be described specifically. It willsufiice to state that the two portions 2a and 2b of the arrangement 2rotate with reference to one another when the conveyor screw 1 isrotated. The biasing spring which is shown in conjunction with thearrangement 2 tends to pass the facing surfaces of the members 2a and 2binto engagement. However, the facing surfaces are not planar but arerather of weavy configuration so that, on such rotation, the member 2aand the member 2b will alternately be separated from one another and bedrawn back together by the biasing spring. This effects axialreciprocation of the conveyor screw 1, which is connected to thearrangement in well known manner and the screw 1 thus alternately ramsagainst the mortar which it has just conveyed into the tap hole TH andthereby compacts and tamps the mortar. Power for rotation of theconveyor screw 1, and thereby also for the axial reciprocation thereof,is supplied by a suitable power means, here illustrated as a pneumaticmotor 3 of conventional construction. By means of a cable or rope 8shown in chain lines in the drawing, the arrangement is suspended fromthe hook 9 of a crane (not illustrated) which is provided for thispurpose.

We have found it advantageous to connect and guide the arrangement withreference to the wall MS by pivoting a dash-pot 7, whose constructionand operation will be self-evident, to the hopper 5 and to the frame 6at the point 7a. Clearly, the dash-pot will tend to draw thearrangement, and of course thereby the front portion of the screwconveyor, deeper into the tap hole TH.

Operation of the device is of course obvious. Material supplied into thefeed hopper 5 will be advanced into the tap hole TH when the motor 3rotates the conveyor screw 1 and thereby axially reciprocates it at thesame time. As the material is expelled from the front end of the screwconveyor, it is tapped and compacted by the repetitive engagement withthe axially reciprocating conveyor screw 1. The dash-pot 7 constantlyurges the screw conveyor deeper into the tap hole TH, and this force ofcourse increased as the tap hole becomes more and more filled and thedevice is forced to withdraw from the tap hole to a greater and greaterextent, thereby opposing the spring in the dash-pot 7. This, of course,in turn results in ever better compacting of the mortar in the tap holeTH.

It will be clear that by resorting to our herein disclosed apparatus thetap hole of an open-hearth furnace or for that matter any analogous holein a masonry structure of a different type and application, can bereliably and tightly closed in a simple and most advantageous manner,and that these high-quality results which are ob tained are reproduciblein every instance in which the same or another hole must be closed inthis manner.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofdevices differing from the types described above.

While the invention has been illustrated and described as embodied in anapparatus which is particularly suitable for closing the tap hole in thewall of an openhearth furnace, it is not intended to be limited to thedetails shown, since various modifications and structural changes may bemade without departing in any way from the spirit of the presentinvention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting features thatfrom the standpoint of prior art fairly constitute essentialcharacteristics of the specific or generic aspects of this invention andtherefore, such adaptations should and are intended to be comprehendedwithin the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims:

1. An arrangement for closing a hole in a masonry structure withhardenable mortar, comprising a furnace having a masonry wall providedwith a hole; screw conveyor means including a conveyor screw having afront portion arranged to extend a substantial distance into the hole,and a rear portion arranged to extend outwardly beyond the hole andincluding also supply means associated with said conveyor screw andoperative for supplying to said rear portion thereof quantities ofhardenable mortar; actuating means connected with said conveyor screwfor rotating the same whereby to convey the mortar toward said frontportion and therebeyond into said hole; and means cooperating with saidactuating means for axially reciprocating said conveyor screw to therebyperiodically advance said front portion into engagement with the mortarin said hole and to tamp and compact such mortar.

2. Arrangement as defined in claim 1, wherein said hole extends inwardlyfrom an exposed outer side of the wall of the furnace, and wherein allaforesaid means are arranged adjacent to said exposed side.

3. Arrangement as defined in claim 1, wherein said screw conveyor meanscomprises an outer tubular housing, and a conveyor screw mounted in saidhousing for rotary and axial movement therewithin.

4. Arrangement as defined in claim 3, wherein said outer tubular housingincludes a cooling jacket arranged for circulation of a cooling fluidtherethrough.

5. Arrangement as defined in claim 1, and further comprising maintainingmeans connecting the first-mentioned means in requisite position withreference to said masonry structure.

6. Arrangement as defined in claim 5, wherein said maintaining meanscomprises a biasing arrangement tending to urge said front portiondeeper into said hole.

7. Arrangement as defined in claim 6, wherein said supply means is rigidwith said rear portion of said screw conveyor means spaced from saidmasonry structure, said maintaining means including a cylinder connectedat one end thereof with said supply means, a piston rod connected at afirst end thereof with said masonry structure and extending with asecond end thereof into the opposite end of said cylinder, and a biasingspring arranged 6 within said cylinder and tending to draw said pistonrod deeper into said cylinder to thereby urge said supply means towardssaid masonry structure and said front portion of said screw conveyormeans deeper into said hole.

8. Arrangement as defined in claim 7, wherein said cylinder and saidpiston rod are pivotably connected to said supply means and said masonrystructure, respectively.

References Cited UNITED STATES PATENTS 1,774,373 8/1930 Hopkins et al26642 2,090,434 8/1937 Thalmann 25-14 X 3,164,860 1/1965 OXel 25103 XROBERT D. BALDWIN, Primary Examiner US. Cl. X.R. 25103

